a) Field of the Invention
The present invention relates to high speed communications systems in general and in particular to devices termed Network Processors used in said communications systems.
b) Prior Art
The use of Network Processors as essential building blocks in communications systems and devices has been on the increase and is expected to continue. It is believed the Network Processor will be as valuable to communications devices as the processor is to the personal computer. As with the processor used in the personal computer, core network functions will be designed into the Network Processor. As a consequence the designer needs only to select a Network Processor with desired characteristics, such as speed, and not be concerned about designing core network functions such as packet routing, classification policing, etc.
Broadly speaking, Network Processors may be divided into two groups, namely: single chip devices and multiple chip devices. With the single chip devices, all the functional components of the Network Processor are fabricated on a single substrate, hence the name single chip. With the multiple chip device the functional components are fabricated on more than one chip, hence the name multiple chips. The present invention primarily relates to the multiple chips type of Network Processor and the single chip type will not be discussed further.
In the multiple chips type of Network Processors the functional components area provided on multiple chips. Proper and effective interconnections of the chips are necessary if the Network Processor is going to function satisfactorily. Proper and effective interconnections relates not only to the hardware, such as busses, used to interconnect the chips but also the protocol that is used to transmit information on the busses or other interconnecting hardware. The interconnection of units termed nodes are well known in the prior art communications technology. The nodes are physically interconnected by some type of communications medium and transmission on the medium is controlled by some type of communications protocol, such as the TCP/IP etc. These protocols are so well known that further discussions are not warranted. Suffice it to say that these well known protocols are effective to interconnect nodes but may not be as effective to interconnect functional components of a system and especially to interconnect functional components of a Network Processor partioned according to the teachings of the present invention set forth herein.
As a consequence there is a need to provide an interface (messages and protocol) to communicate between functional components of a Network Processor partitioned as set forth herein.